Italian meringue buttercream (IMBC) can be made ahead and refrigerated for up to a week or even frozen up to a month, but if it is not used right away when it is nice and creamy, there are a few extra steps you need to take. If the buttercream has been frozen, it should be defrosted in the fridge overnight. Refrigerated buttercream will be quite firm – as hard as a chilled stick of butter as seen above – and cannot be whipped smooth at this point. Follow these instructions to reconstitute it. Once softened, you can spread it smoothly and easily.
P.S. Although IMBC is made with a balloon whisk, we often use the flat paddle attachment of our stand mixer when we are bringing it back to life. It’s your choice and experience will help you decide which attachment to use. Note that upon reconstituting IMBC, you most likely will lose a little volume.
- One method is to take the container it is stored in and, if it is microwaveable, place it in the microwave on a very low power and heat in 15 second spurts, assessing softness each time. You want it to be brought to room temperature uniformly without melting the butter. This technique will depend on your familiarity with your microwave. Be patient and it will work.
- Alternatively, have the bulk of the IMBC in your mixer bowl and microwave a small amount until very soft (too soft), then use it to “seed” the larger batch. The two portions will equalize one another. You might have to play with this technique and nuke a small amount a few times.
- Another technique is to place a quantity of cold buttercream in the stainless steel bowl of your stand mixer and place it over an extremely low heat on top of the stove. A flame tamer can help immeasurably here, which is a flat disc that goes on top of your burner and reduces the amount of heat that reaches whatever is placed upon it. Hold the bowl with one hand and constantly stir the chunks of buttercream, folding the pieces over each other so that no one piece is constantly on the bottom receiving too much heat. Experience makes a difference here. Once you do this a few times, these instructions will make perfect sense. You want to warm the buttercream, but not melt the butter out. Be careful.
- A subtler approach to the above is to do it over a water bath.
- A fifth technique is to place a quantity of buttercream in your mixer bowl and aim a hair dryer on the outside of the bowl, and even directly on top of the IMBC. Watch carefully, and as described above, you want to warm it, not melt it.
After you have warmed up your buttercream, whip it with the flat paddle or balloon whisk until smooth and creamy. Heat again if it is still lumpy; chill if too soupy. It is best to be conservative and heat it slowly than to melt the butter and end up with sweet soup. Your buttercream is now ready to use.
The only time this didn’t work in my 30 years of playing with IMBC was when I had a batch that had been frozen and defrosted a few times. It seemed “tired” and just would not come back together. Other than that, it has worked. Every. Time. We hear people give up too early all the time. The issue is that it is usually still too cold. It will look lumpy and lack creaminess. If any of the above techniques aren’t working, we promise it’s just about temperature. Keep trying. It’s either too cold or too warm. You can do it!
Image: Peter Muka